Synthesis and Evaluation of 2-Acrylamido-2-Methyl-1- Propane Sulfonic Acid Based on Core-Shell Nanogels for Preconcentration of Fe (III) Ions from Aqueous Solutions and their Determination in Real Water Samples

Synthesis and Evaluation of 2-Acrylamido-2-Methyl-1- Propane Sulfonic Acid Based on Core-Shell Nanogels for Preconcentration of Fe (III) Ions from Aqueous Solutions and their Determination in Real Water Samples

In the present study, poly(2-acrylamido-2-methyl-1-propanesulfonic acid -co-N-isopropylacrylamide) hydrogels, were synthesized by free- radical crosslinking solution polymerization with different ratios of monomers to form colloidal hydrogels shell around poly(vinyl alcohol) core through epichlorohydrine, in order to obtain well-define PVA(AMPS-NIPAm) core/shell nanogels with diameter nearly 30 nm. The prepared nanogels were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Transmission electron microscopy (TEM) and Scanning electron microscopy (SEM). These Nanogels were used effectively for removal of Fe(III) ions from aqueous solutions. The factors affecting adsorption such as pH, contact time, initial concentration, temperature, ionic strength, desorption, interfering ions, and analytical application for real water samples were succefully investigated. The maximum capacity of Fe(III) ions was 320, 202 and 98 (mg/g) for PVA/p(90AMPS-10NIPAm), PVA/ p(50AMPS-50NIPAm) and PVA/p(10AMPS-90NIPAm), (wt.:wt. %), respectively. The adsorption isotherms and kinetics were determined; the equilibrium data matched well with the Langmuir model. The pseudo second-order model described the adsorption process better than the pseudo first-order model. Thermodynamic parameters revealed that a spontaneous and exothermic nature is identified in all cases of adsorption process.